The present invention generally relates to obtaining accurate readings of a moving device, such as a rotating disk. The present invention more particularly relates to obtaining an accurate remote reading of a rotating disk of a utility meter and detecting and preventing tampering and theft of utilities.
Electrical metering of residential energy has historically been accomplished using electromechanical meters that sense electromagnetic fields in proximity to voltage coils and current carrying conductors. These electromechanical meters are generally effective in metering electrical energy consumption, but are incapable of providing, in a cost effective manner, numerous additional functions currently being demanded by the utility industry. For example, modern utility companies desire metering devices capable of metering, not only total energy consumption, but also many other electrical parameters (e.g., time-of-use).
The industry has responded to this demand by developing completely electronic metering devices. Electronic meters effectively provide the utility with measurements of a number of electrical parameters, as well as many other advantages. For example, to reduce the costs associated with reading meters, utility companies often use electronic metering devices with built-in communications modules capable of communicating meter reading data back to the utility""s master station. Such communications networks obviate the need for human meter readers to go to individual subscriber locations to read meters. While such meters may be highly desirable for new installations, replacing existing meters with new, fully electronic meters is generally deemed cost prohibitive.
Various systems and methodologies have been utilized in the past for performing remote reading functions. There are, however, various problems and shortcomings with the methodologies employed in the past. It is often important to provide a remote meter reading system that is easily retrofitted to existing utility meters. Of course, it is particularly important that such retrofitted reading systems fit within the present or available space confines.
Prior methods for remote meter reading have included several different characteristics. In one method, low power radio frequency (RF) transmitters are configured in the utility meters that are capable of transmitting the utility consumption data to a remote location. For instance, RF transmitters can be applied so that utility personnel can simply drive through a neighborhood and remotely collect the meter consumption data by receiving the RF signal. This permits the utility companies to read the meters without having to physically access each individual meter, leading to faster and more efficient collection of meter readings. In another prior method, cellular transmitters are configured into the utility meters that can then transmit the utility consumption data back to the utility company. Additionally, the utility meter can be directly connected to a phone line and then utility consumption data can then be routinely transmitted over phone lines. After collection of the consumption data, the data is communicated to a central station (i.e. the utility company) through a gateway and a wide area network (WAN), such as the Internet. The data can then be analyzed and monitored using an appropriately configured computer and database. Although each of the aforementioned methods of remotely collecting utility consumption data is convenient and efficient for the utility companies, it does not address the concern of the accuracy of the readings and the detection of tampering with the utility meter.
When reading remotely, the utility company could simply xe2x80x9creadxe2x80x9d the index by implementing devices that interpret the movement of the dials that comprise the index and convey that data to a remote location. However, utility companies desire readings with greater accuracy and the ability to determine whether someone has tampered with the utility meter. Therefore, the utility companies desire the ability to monitor and count the revolutions of the rotating disk of the utility meter. One method for increasing the accuracy of remote meter reading has involved painting or marking a black stripe on the underside of the disk, and configuring an optical sensor to read and count the number of times the black stripe passes the optical reader, and then transmitting the data to a receiver. This approach, however, suffers several drawbacks.
First, it is often difficult to obtain accurate and reliable readings. Although the disk is silver in color, it does not always provide a good reflectivity. Consequently, the contrast between the black stripe and disk may not be as xe2x80x9celectrically readablexe2x80x9d as desired. Empirical tests have shown that, on a three volt scale, often only a 0.8 volt difference is measured between readings of the black stripe and the silver disk. These readings are further compromised by the fact that the paint or marker typically fades over time, and that good/definable edges are often not present on the black stripe. Faded color and poorly defined edges lead to misreadings and, therefore, inaccuracy in the remote reading system.
A second shortcoming of this type of system is its failure to determine when the disk is not moving or when the disk is rotating in a reverse direction. Theft of electricity has increased in recent years, and many consumers have discovered ways to bypass electrical meters or otherwise cause the disk to stop rotating for extended periods of time. Still other consumers have discovered ways to actually cause the disk to rotate in a reverse direction. With the marking or painting system it is difficult, if not impossible, to detect and prevent these and other types of electricity theft.
In U.S. Pat. No. 5,086,292 to Johnson et al., a system for detection of tampering with a utility meter is disclosed. In Johnson, a utility meter is outfitted with a plurality of sensors which monitor the tilt, electric field, magnetic field, temperature, sound, reverse rotation and movement of the rotating disk. However, the invention of Johnson is not easily retrofitted to existing utility meters and requires extensive circuitry and software support in order to adequately perform its tamper detection and electricity consumption monitoring functions. Similarly, in U.S. Pat. No. 6,100,816 to Moore, an adapter device is disclosed which remotely monitors consumption and is retrofittable to existing utility meters. However, the Moore adapter module device requires substantial space to mount the device to a utility meter and additionally requires direct linkage to the original meter""s dials and a plurality of other moving parts in order to monitor electricity consumption. Furthermore, because the Moore device is retrofitted to the outside of the existing utility meter it is more prone to tampering.
Accordingly, it is desired to provide an improved system that addresses and overcomes the aforementioned deficiencies and inadequacies of the prior art.
The present invention provides a system and method for obtaining an accurate reading of a utility meter. Additionally, the present invention provides a system and method for determining tampering with utility meters and theft of electricity.
Briefly described, in architecture, the system can be implemented as follows. The present invention utilizes a reflective tape affixed to the rotating disk of a utility meter. This reflective tape is constructed so as to have sections of highly reflective material and non-reflective material, separated by clearly defined edges. Thus, the difference between the reflective areas and the non-reflective areas provides a high degree of contrast and facilitates the xe2x80x9creadabilityxe2x80x9d of the tape. As the disk rotates with the use of electricity, the tape is xe2x80x9creadxe2x80x9d by an optical sensor that is connected to a circuit card. The circuit card is retrofittably mounted in available space within the utility meter so that the optical sensor aligns with the tape as it is carried through its revolutions. By xe2x80x9creadingxe2x80x9d the passage of the reflective and non-reflective sections of the tape, the consumption of electricity and the rotational direction of the disk can be accurately determined. The consumption data is then communicated to the circuit card and then transmitted to the utility company.
The present invention can also be viewed as providing a method for retrofitting existing utility meters so as to obtain more accurate meter readings and detect unauthorized use or tampering with utility meters. In this regard, the method can be broadly summarized by the following steps: applying a light-weight, highly-reflective tape, such as mylar tape, to the rotating disk of a utility meter and installing an optical sensor and circuit card in such a manner that the optical sensor aligns with and xe2x80x9creadsxe2x80x9d the tape as it is carried through its revolution on the disk. The reflective tape is marked with sections of non-reflective material and the contrast between these sections is xe2x80x9creadxe2x80x9d by the optical sensor and the results communicated to the circuit card. The consumption data is then transmitted to the utility company for analysis and monitoring.
Other systems, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.